def Expose(func):
"""
This is to prevent methods that aren't supposed to be able to be
called from being called through wild-card method-name-based
routing systems.
"""
# Checks to make sure that the method has not been previously prevented from
# being exposed (Currently only a Filter would do this).
if func.__dict__.has_key('Expose') and func.Expose is False:
raise AttributeError, 'Method cannot be exposed _and_ be a filter at the same time!'
func.Expose = True
return func
class Filtering(object):
"""
Class for setting functions of controllers to be filters.
Priority defines their sort order. Filters are sorted by priority (With 0
being the lowest priority) and then alphabetically (With "A" coming first).
"""
def filter(self, func):
# Checks to make sure that the method has not been exposed, since filters
# should not be exposed.
if func.__dict__.has_key('Expose') and func.Expose is True:
raise AttributeError, 'Method cannot be a filter _and_ be exposed at the same time!'
func.Expose = False
# Functions that handle the decorators.
def Before(self, func):
self.filter(func)
func.Filter = 'Before'
func.Priority = 0
return func
def After(self, func):
self.filter(func)
func.Filter = 'After'
func.Priority = 0
return func
# Initialize the Filtering class and put it in the namespace as Filter.
Filter = Filtering()
class Controller(object):
"""A controller for processing requests."""
# Example of using the Before and After filters and exposing methods.
# * The append() method is used because it's the easiest, clearest, and
# simplest way of doing this, and avoids unnecessary abstraction.
#@Filter.Before
#def my_before_filter(self):
# pass
#my_before_filter.Priority = 5
# ^ Optional priority definition, the higher numbered filters are executed first.
#@Expose
#def my_exposed_method(self):
# pass
def _filter_for(self, filter_type):
"""
Iterates through the methods of the Controller and finds methods with a
Filter attribute that is equal to filter_type.
"""
filters = []
for item in dir(self):
if not item.startswith('__'):
method = self.__getattribute__(item)
try:
if method.Filter is filter_type:
filters.append(method)
else: continue
except AttributeError: continue
else: continue
filters.sort(key=lambda obj: (obj.Priority * -1))
return filters
def before_filters(self):
return self._filter_for('Before')
def after_filters(self):
return self._filter_for('After')
